From: martin rudalics <rudalics@gmx.at>
To: Paul Eggert <eggert@cs.ucla.edu>,
Stefan Monnier <monnier@IRO.UMontreal.CA>,
emacs-devel@gnu.org
Subject: Re: [Emacs-diffs] emacs-26 9bf66c6: Don't run FOR_EACH_FRAME when there's no frame left (Bug#29961)
Date: Sun, 17 Dec 2017 11:46:33 +0100 [thread overview]
Message-ID: <5A364B09.4020905@gmx.at> (raw)
In-Reply-To: <9d0b9c22-d386-cd0a-3947-a44d58b1ee0e@cs.ucla.edu>
> The code with undefined behavior is in delete_frame, after its 3rd use
> of FOR_EACH_FRAME. This loop head is of the form 'FOR_EACH_FRAME
> (tail, frame1) ...' and the code after the loop assumes that frame1 is
> initialized, an assumption that is false if Vframe_list is nil.
Sorry for being completely dense but
eassume (CONSP (Vframe_list));
now means that we can assume that `frame-list' is non-empty. Isn't that
assumption incorrect in the scenario of the bug we're discussing here?
>> Neither next_frame nor prev_frame exhibit such behavior IMO.
>
> That's right. However, commit 8720f601e715e5f1d41f7cf863a525a1cc1bc12c
> removed these functions' assertions that frame-list is non-nil, so I
> thought it wise to resurrect them.
I don't think that these assertions did any good and would remove them
at least on master.
martin
next prev parent reply other threads:[~2017-12-17 10:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20171215073120.7671.79446@vcs0.savannah.gnu.org>
[not found] ` <20171215073122.52703204D3@vcs0.savannah.gnu.org>
2017-12-15 16:23 ` [Emacs-diffs] emacs-26 9bf66c6: Don't run FOR_EACH_FRAME when there's no frame left (Bug#29961) Stefan Monnier
2017-12-15 17:13 ` Paul Eggert
2017-12-15 18:17 ` martin rudalics
2017-12-15 19:09 ` Paul Eggert
2017-12-16 9:42 ` martin rudalics
2017-12-17 0:50 ` Paul Eggert
2017-12-17 10:46 ` martin rudalics [this message]
2017-12-18 0:39 ` Paul Eggert
2017-12-18 7:26 ` martin rudalics
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